Frederick Aloys Hahn was an American professional baseball pitcher who worked in one game in Major League Baseball (MLB) for the St. Louis Cardinals in 1952. Despite his brief MLB tenure, Hahn, a left-hander from Nyack, New York, had a 13-year (1947–1959) professional career. He was listed as 6 feet 3 inches (1.91 m) tall and 174 pounds (79 kg).